1) Field of the Invention
The present invention relates to a power system of a clothes washing machine and, more particularly, to a power system of a washing machine which can suppress the rotation of a spin basket during a washing operation and rotate the spin basket at a high speed during a spin drying operation.
2) Description of the Related Art
Generally, a washing machine includes a main body defining an outer configuration thereof, a water tub installed within the body, and a spin basket and a pulsator mounted within the water tub. A power system for driving the spin basket and pulsator is mounted under the water tub.
The power system conventionally comprises a motor, a power transmission system, and a belt for connecting the motor to the power transmission system. This will be described hereinbelow with reference to FIG. 7.
As shown in FIG. 1, a conventional power system comprises a power transmission system 100 and a driving motor (not shown). The power transmission system 100 has a hollow dehydrating shaft 101 (so-called because it rotates the spin basket), and a laundering shaft 102 (so-called because it operates the pulsator) inserted into the hollow portion of the hollow dehydrating shaft 101. The laundering shaft 102 is divided into upper and lower portions, with a planetary gear unit 103 being disposed therebetween. The planetary gear unit 103 shifts between different rotating speeds. A brake band 104 and a brake lever 105 are disposed beside the dehydrating shaft 101 so as to brake rotation of the dehydrating shaft 101 during washing and rinsing stages. A one-way bearing 106, allowing the dehydrating shaft 101 to rotate in only one direction, is mounted on an outer circumference of the dehydrating shaft 101. In addition, a clutch spring 107 and a clutch lever 108 for transmitting/interrupting power from the motor to both the dehydrating shaft 101 and the laundering shaft 102 are mounted under the one-way bearing 106. A pulley 109 on which a belt (not shown) is engaged is mounted on a lower end of the laundering shaft 102.
In this conventional power transmission system 100, torque of the motor is selectively transmitted via shaft 102 to the pulsator 111 or via shaft 101 to the spin basket 110 by means of the clutch spring 107, thereby performing the washing and dehydrating operations. To achieve this, it is necessary that the clutch spring 107 has a high tensile strength to permit or interrupt the transmission of torque from the motor to the dehydrating shaft 101 and the laundering shaft 102, both of which are rotated at a high speed. However, the manufacturing process for such a spring having high tensile strength is complicated, and, as a result, manufacturing costs are increased.
In addition, the brake band 104 for preventing the spin basket 110 from idling (rotating) during the washing operation is, when it brakes the spin basket 110 in one direction, subjected to high resistance against force generated when the spin basket 110 is exerting force to rotate in an opposite direction by a water current within the water reserving basket. The above described one-way bearing 16 must thus be used, making the structure complicated and increasing manufacturing costs. Finally, an unpleasant noise is generated during the braking operation of the brake band.
As described above, the conventional power system of a washing machine is complicated with regard to the arrangement of parts for performing the washing, dehydrating and braking operations, making it difficult to manufacture the same and increasing manufacturing costs. In addition, because of the large number of parts needed for this complicated arrangement, much space is required which, in turn, acts to increase the overall size of the washer.